Method and apparatus for mechanicalfluid power conversion



Oct. 7, 1969 R. s. CATALDO 3,470,820

METHOD AND APPARATUS FOR MECHANICAL-FLUID POWER CONVERSION Filed May 2, 1968 Roy 5 (aria/0'0 United States Patent M 3,470,820 METHOD AND APPARATUS FOR MECHANICAL- FLUID POWER CONVERSION Roy S. Cataldo, Birmingham, Mich., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed May 2, 1968, Ser. No. 726,082 Int. Cl. F04b 19/00 US. Cl. 1031 Claims ABSTRACT OF THE DISCLOSURE Method and apparatus are disclosed for converting between mechanical and fluid power by positive displacement fluid action and direct fluid power transformation. In the preferred embodiment of the apparatus mechanical power is converted into fluid power and vice-versa by a unidirectionally acting piston with the fluid power transformed by direct fluid power transformation by fluid gyrator action which controls fluid impedance.

The invention relates to a method and apparatus for converting between mechanical and fluid power and more particularly to such a method and apparatus employing direct fluid power transformation with fluid impedance control.

In my copending United States patent application Ser. No. 593,049 filed Nov. 9, 1966 and entitled Method and Apparatus for Transforming Fluid Power, now Patent No. 3,401,63 8, I disclosed my method and what I termed fluid gyrator transformer apparatus for converting or transforming fluid power by spinning a primary fluid flow about an axis transverse to the flow to induce a secondary fluid flow having different flow and pressure values. This is accomplished without producing substantial resultant centrifugal forces in the flow directions and provides the two flows with impedances which are functions of the spin velocity, fluid impedance being the ratio of differential pressure to flow. I will now show that my basic fluid gyrator transformer may be converted into a unidirectional fluid pump or motor by the interposition of a rotary piston. The basic mechanical-fluid power converter unit, which I term either a gyrator pump or motor depending on whether it is receiving a mechanical input or delivering a mechanical output, comprises a rotor having a reaction chamber centered on the rotors spin axis. A pair of fluid passages provided in the motor, and thus rotatable with the reaction chamber, direct primary and secondary fluid flows to and from the reaction chamber in primary and secondary, substantially radial, flow directions which are perpendicular to each other and the spin axis. One of the fluid passages is provided with an annular shape and a rotary piston mounted in the annular passage is rotatable through the reaction chamber.

When the gyroscopic mechanical-fluid power converter unit is used as a pump, external power is delivered to drive or rotate the piston. The piston operates in the annulus as a positive displacement type device to convert mechanical power into fluid power which is represented by the establishment of a primary fluid flow and pressure in the annulus. The rotor is spun to continuously transform the primary fluid flow and pressure at the reaction chamber by gyroscopic action into secondary fluid flow and pressure in the other or secondary flow passage. This is accomplished without producing substantial resultant centrifugal forces in either of the flow directions and provides the two flows with impedances which are a function of the spin or rotor velocity, the secondary flow and pressure representing the output of the unit when it acts as a pump.

The gyroscopic mechanical-fluid power converter unit is reversible in that, when a primary flow and pressure is 3,470,820 Patented Oct. 7, 1969 established in what was before referred to as the secondary passage, spinning of the rotor converts such fluid flow and pressure by gyroscopic action into secondary flow and pressure in the annulus to drive the piston, i.e., the unit then acting as a motor, and with the fluid impedances of the two flows being a function of the spin speed.

In one embodiment of my gyroscopic pump-motor unit, I provide a fixed speed ratio between the rotor and the piston to eflfect fluid impedances that are a function of the square of piston speed. In another embodiment, I provide separate drives to the rotor and piston to effect fluid impedances that are a function of the product of rotor or spin speed and piston speed.

An object of the present invention is to provide a new and improved rnethod and apparatus for mechanical-fluid power conversion.

Another object is to convert between mechanical power and fluid power with a unidirectionally acting piston operating in a gyroscopic fluid force field.

Another object is to provide a method and apparatus for converting between mechanical and fluid power with unidirectional rotary piston action and direct fluid power transformation.

Another object is to provide a gyroscopic pump having positive displacement fluid action combined with fluid gyrator action for converting mechanical input power to fluid power with controlled fluid impedance.

Another object is to provide a gyroscopic motor having fluid gyrator action combined with positive displacement fluid action for converting fluid input power to mechanical output power with controlled fluid impedance.

Another object is to provide a method and apparatus for inducing a secondary differential pressure and flow by the establishment of a primary differential pressure and flow by operation of gyroscopic action with either the primary fluid power established by positive displacement fluid action in the gyroscopic fluid force field with mechanical input or the secondary fluid power converted to mechanical output power by positive displacement fluid action in the gyroscopic fluid force field.

These and other objects of the present invention will be more apparent from the following description and drawing in which:

FIGURE 1 is a longitudinal view with parts in section of a gyroscopic mechanical-fluid power converted unit with a fixed ratio between rotor speed and piston speed constructed according to the present invention.

FIGURE 2 is a view taken on the line 22 in FIG- URE 1.

FIGURE 3 is a view taken on the line 3-3 in FIG- URE 1.

FIGURE 4 is a longitudinal view with parts in section of separate drives to the rotor and piston shown in FIGURE 1.

In my above-mentioned copending patent application Ser. No. 593,049 now Patent No. 3,401,638, I disclosed what I termed a fluid gyrator having a spinning reaction chamber at the intersection of primary and secondary flow passages which are fixed to rotate with the reaction chamber. The power represented by an established primary flow and differential pressure in the primary passage is converted by the gyrator into secondary flow and differential pressure in the secondary passage with the primary and secondary fluid impedances a function of the spin velocity.

In accordance with the present invention, a rotary piston is interposed in a fluid gyrator type structure to provide what I have termed a gyroscopic mechanicalfluid power converter device which is operable either as a pump or motor.

Referring to FIGURE 1, the gyroscopic, mechanicalfluid power converter unit, which is generally designated as comprises a rotor 12 supported on a stationary frame 14 for rotation about a spin axis 16. Rotor 12 is supported for this rotation at one rotor end by a ball bearing 18 and at the other rotor end by shafting and bearing means as described in more detail later. Rotor 12 is connected to be driven by a suitable spin drive power source dependent upon the application of the unit as later described.

Rotor 12 has both a looped flow passage 20 as shown in FIGURE 1 and a cylindrical chamber 22 as shown in FIGURE 2 which intersect at a reaction chamber 24 which is generally rectangular in shape and centered on spin axis 16. Passage 20 is for directing fluid to and from the reaction chamber 24 to and from an external system. Passage 20 comprises a leg 26 having a circular flow area 28 centered on the spin axis 16 at the right end of the rotor as shown in FIGURES 1 and 3. Leg 26 gradually turns outward from the spin axis and then makes a smooth bend radially inwardly to meet reaction chamber 24. The other leg 30 of passage 20 projects radially outward from the reaction chamber diametrically opposite from leg 26 and gradually bends inwardly towards the spin axis with the bend occurring at the same radius as leg 26. Leg 30 has the same flow area shape as leg 26 until it saddles leg 26 as shown at one axial location by the quarter-moon flow are a shape 31 in FIGURE 3. Leg 30 terminates at the right end of the rotor with an annular flow area 32 concentric with the circular flow area 28 of leg 26.

Both the legs 26 and 30 of passages 20 are connected to stationary fluid passages for delivering fluid to and from passage 20 to and from the external system being serviced. The coupling comprises a collar 34 integral with frame 14. Collar 34 has a bore 35 centered on spin axis 16 and in which a tube 36, also centered on the spin axis, is secured by streamline struts 38. The interior of tube 36 provides a stationary fluid passage 40 mating with leg 26 of passage 20 at the right end of the rotor. A stationary annular fluid passage 42 provided by the exterior of tube 36 and bore 35 mates with leg 30 of passage 20 at the right end of the rotor. The right end of rotor 12 and left end of collar 34 having overlapping lips and the opposed end faces of the rotor 12 and the collar 34 and tube 36 have rubbing contact to provide sealing between the passage legs 26 and 28 and their connection with the stationary passages 40 and 42.

For converting between mechanical and fluid power without producing unbalanced centrifugal fluid forces, the cylindrical chamber 22 has its axis 44 perpendicular to and intersecting the spin axis 14 as shown in FIGURES 1 and 2. A piston 46 having opposed, radially extending face portions 48 is rigidly secured to a shaft 50 which is journaled in rotor 12 for rotation about the cylinders axis 44. The rotary piston 46 and chamber 22 provide a mechanically balanced positive displacement type device having an annular flow passage 52 which intersects the looped flow passage 20 at right angles at the reaction chamber 24.

In my above-mentioned copending application Ser. No. 593,049 now Patent No. 3,401,638, I showed that what I termed a basic fluid gyrator element is essentially a substantially lossless fluid impedance converter and that the fluid phenomenon occurring may be shown to be based upon the Coriolis forces acting upon a fluid element. 1 will now show that my gyroscopic mechanicalfluid power converter unit 10 is operable as either a pump or motor and that with the existence of a primary flow in one of the passages 20, 52 and a primary differential pressure across the reaction chamber 24 the power represented by such primary flow is continuously converted in the reaction chamber to secondary flow in the other passage and secondary differential pressure across the reaction chamber by continuously spinning the rotor 12. When piston 46 is receiving a mechanical input the unit operates as a pump and when the piston is delivering a mechanical output the unit operates as a motor. In either instance the fluid impedance or ratio of differential pressure across the reaction chamber to flow in each passage is a function of the annular spin velocity about spin axis 16.

In the case of mechanical to fluid power conversion, i.e., pump operation, external mechanical input power is delivered to piston 46 by suitable power input or piston drive means to continuously rotate the piston in either direction while the rotor 12 is caused to spin in either direction by suitable spin or rotor drive means, the preferred piston drive means and rotor drive means that are shown being described in detail later. For example, the piston 46 and rotor 12 may be simultaneously rotating in the directions indicated by the arrows in FIGURES 1 and 2. For these directions of rotation, fluid is made available to unit 10 such as from a reservoir via the stationary center passage 40 and the stationary annular passage 42 is connected to deliver fluid from the unit to a system requiring fluid under pressure. With fluid in the units rotary fluid circuit, the rotating piston 46 induces, in the case of pump operation, a primary flow in the annular passage 52 in the direction indicated by the arrow in FIGURE 2 by positive displacement action. With rotor 12 spinning and thus the reaction chamber 24 and with the primary flow through the reaction chamber, the power delivered to the fluid by the positive displacement action serves as the input fluid power to the gyroscopic converter section of the unit. The gyroscopic converter section converts the input fluid power at reaction chamber 24 into secondary fluid power which is represented by the establishment of secondary flow in passage 20 in the direction indicated by the arrows with leg 26 acting as the suction side of the pump and leg 30 acting as the discharge side of the pump.

Alternatively, the unit 10 operates as a motor by delivering fluid under pressure from an external source to establish a primary flow in passage 20 which is directed through the reaction chamber 24. With the rotor 12 spinning, there is induced by the gyroscopic action a secondary flow in the annular passage 52. The secondary flow drives the piston 46 thereby providing fluid to mechanical power conversion and the piston in this case would be connected to drive a load. Furthermore, when the unit is being operated as either a pump or a motor, reversal of either rotor spin direction or primary flow direction reverses the secondary flow direction without affecting either the principles of operation or the efliciency of the unit.

My method and apparatus for producing both pump and motor operation may be shown to be based upon the Coriolis forces acting upon a fluid element. The several advantages of the above-described method and apparatus for producing same will become more apparent from the equations presented below whose nomenclature is associated with the structure of my unit.

Considering first that the mechanical-fluid power converter unit 10 is operated as a fluid gyrator pump the torque reaction or mechanical input torque requirements in terms of Coriolis spin speed and secondary fluid flow and assuming no losses may be written as:

where T =Primary fluid torque=Torque on piston 46 p=Weight of fluid g=Acce1eration of gravity R =Primary flow radius=Means face radius of piston 46 V=Volume of reaction chamber 24 A =Secondary flow area=Flow area of passage 20 Q =Secondary fluid flow=Volumetric flow in passage 20=V/ time W =Coriolis angular velocity =Angular velocity of secondary flow in passage 20=Angular velocity of rotor 12 W =Angular velocity of primary flow in passage 52=Angular velocity of piston 46 The secondary differential pressure (AP may be written from Equation 1 as:

AP,: g s

U =W R =Linear velocity of primary flow in passage 52=Elfective linear velocity of piston 46 Equation 2 gives the differential pressure across the secondary terminals of the gyrator pump, i.e., between the points of connection of passage 20 with reaction chamber 24. Compared with a conventional axial flow pump or compressor having a single set of rotor blades and a single set of stator blades my gyrator pump potentially provides twice the maximum pressure rise through a single stage axial flow machine. Furthermore, my gyrator pump potentially provides higher pressure ratios than centrifugal machinery at least for adiabatic compression.

When my gyrator unit is used as a motor, the secondary power is the output mechanical power at the piston and is given by the following equation using similar nomenclature applied to the structure for motor operation with the assumption that there are no losses:

UOU, y

where U =Eifeotive linear Coriolis velo0ity=-l W A =Secondary flow area=F1ow area of passage 52 Comparing the gyrator motor power from my unit with the power from an impulse turbine another important advantage of my gyrator unit becomes more apparent recognizing that turbine equipment has relative velocity between the fluid and blades which gives rise to shock losses. In my gyrator structure with the unidirectionally acting piston there is no relative velocity between the fluid and mechanical members. Furthermore, there is no fluid spin velocity relative to the rotor and therefore the losses are limited to fluid friction losses within pipes and mechanical losses.

From the above it is seen that my gyrator structure is governed by the same Coriolis force equation as other gyroscopic devices and has substantially lossless fluid impedance converter characteristics with the interposition of the unidirectional rotary piston providing for the conversion between mechanical power and fluid power, i.e., a fluid pump or motor having impedance-transforming properties. Furthermore, my structure also provides for holding fluid losses to laminar flow losses. In addition, the energy required to bring the fluid up to spin speed is equal to the energy given up to the spin axis by virtue of Coriolis forces. It is also seen that the spin velocity of my gyroscopic power converter unit plays essentially the same role as flux density plays in the case of electrical conversion devices. Another advantage is that increasing the spin velocity reduces the required size and weight of my device. My fluid gyrator pump-motor unit is useful in a large variety of applications since in addition to mechanical-fluid power conversion, my unit is operable to provide regulated pressure flow and torque as determined by the relationship between rotor speed and piston speed.

-I have thus far shown that my gyroscopic, mechanicalfluid power converter unit 10 is operable as either a pump or motor depending on whether there is mechanical or fluid power input. In either case spin velocity is provided to rotor 12. The drive to the rotor depends on the particular application of my device which may have a fixed speed ratio or a variable speed ratio between the rotor and piston.

In the case of the fixed speed ratio, the rotor is drivingly connected to the mechanical path which includes the piston and thus is input driven for pump operation and output driven for motor operation. Such an arrangement is shown in FIGURE 1 and comprises a power shaft 54 supported by a ball bearing 56 in the left end of a gear housing 58 mounted on frame 14. The power shaft 54, rotor 12 and piston 46 are drivingly connected by gearing comprising a gear set 60 mounted in housing 58.

In the gear set 60 there is provided an internal toothed annular spur gear 62 integral with power shaft 54. Gear 62 meshes with one spur gear 64 of a cluster gear member 66 journaled in web 68 of housing 58.

The driving connection with rotor 12 is provided by meshing cluster gear 64 with a spur gear 70 which is integral with a shaft 72 axially aligned with the spin axis 16. Shaft 72 is piloted at its left end in the right end of the power shaft 54 by a sleeve bearing 74 and is rigidly secured at its right end to the left end of rotor 12 by a spline connection 76. Shaft 72 is supported at an intermediate point in web 68 by a ball bearing 77. Thus, the power shafts bearing 56 and bearing 77 support the left end of rotor 12 on the frame.

The driving connection with piston 46 is provided by meshing the other cluster gear 78 with an idler gear 79 supported on web 68. Idler gear 79 meshes with an external toothed annular spur gear 80. Gear 80 is supported by a ball bearing 81 in the right end of gear housing 58 for rotation about the spin axis free of the rotor drive shaft 72 which extends therethrough. Gear 80 is integral with an annular bevel gear 82 through which the rotor drive shaft 72 also freely extends, there being provided a pilot sleeve bearing 83 between shaft 72 and gears 80 and 82'. Bevel gear 82 meshes with another bevel gear 84- secured to the piston shaft 50.

In the FIGURE 1 drive arrangement for the piston and rotor, the power shaft 54 provides for mechanical power input in the case of pump operation and mechanical power output in the case of motor operation. In either case the rotor and piston have a fixed speed ratio and rotate in the directions indicated by the arrows as provided by the gearing. Since the rotor and piston have a fixed speed relationship the fluid impedances in unit 10 are thereby made a function of the square of rotor speed which is particularly useful in normal pump or motor applications of my device.

In the case of the variable speed ratio, separate drives are provided to the rotor and piston. Such an arrangement is shown in FIGURE 4 and is used in place of the gearing in the gear housing shown in FIGURE 1. Since certain parts in FIGURE 4 are similar, like reference numerals are employed for identifying corresponding parts with such numerals appearing in FIGURE 4 being primed. In the FIGURE 4 arrangement the rotor drive shaft 72' connected to rotor 12 is supported by a ball bearing 86 in the left end of gear housing 58 and connected directly to a spin or rotor power source such as a variable speed motor 88 having a speed control 90. The power shaft 54 is offset from the rotor drive shaft and supported by the ball bearing 56' in the left end of housing 58. In the gear housing a spur gear 92 integral with the inboard end of power shaft 54' meshes with an annular external toothed spur gear 94. Gear 94 is integral with the bevel gear 82' and both gears are supported by the ball bearing 81 in the right end of housing 58, the rotor drive shaft extending freely through these gears and being piloted by the sleeve bearing 83'.

In the FIGURE 4 drive arrangement for the piston and rotor, the power shaft 54 again provides for mechanical power input in the case of pump operation and mechanical power output in the case of motor operation. The spin speed of rotor 12 is independent of piston speed and provided by the variable speed motor 88. Since the rotor 12' and the piston which is connected to bevel gear 84' have a variable speed relationship the fluid impedances in my converter unit are thereby made a function of the product of rotor speed and piston speed. The independent spin or rotor speed provided by operation of the motor control 90 controls the fluid flow or speed and torque or pressure in the converter unit which is particularly useful in pump or motor applications to provide such regulation without conventional regulating devices in the system to which my unit is connected.

The above described preferred embodiments are illustrative of my invention which may be modified within the scope of the appended claims.

-I claim:

1. A method of converting between mechanical power and fluid power comprising the steps (1) establishing a primary fluid flow through a reaction zone in a direction substantially perpendicular to a spin axis; (2) spinning the fluid about the spin axis while it passes through the reaction zone to convert by action of the spinning fluid at the reaction zone the power represented by the primary fluid flow into secondary fluid flow in a direction substantially perpendicular to the spin axis and transverse to the primary flow direction; (3) converting between mechanical power and the power represented by one of the fluid flows at the reaction zone.

2. The method set forth in claim 1 and (4) establishing a fixed speed relationship between the fluid spin speed and the speed of the mechanical power to provide the fluid flows with impedances that are a function of the square of the fluid spin speed.

3. The meethod set forth in claim 1 and (4) varying the fluid spin speed independently of the speed of the mechanical power to provide the fluid flows with impedances that are a function of the product of the fluid spin speed and the speed of the mechanical power.

4. A mechanical-fluid power converter comprising rotor means having a reaction chamber centered on the rotors spin axis and a pair of fluid passage means for delivering fluid to and from said reaction chamber in transverse directions that are substantially perpendicular to said spin axis; one of said fluid passage means providing an endless fluid passage; piston means supported by said rotor means for movement in said endless passage and through said reaction chamber; piston drive means drivingly connected to said piston means for imparting movement to and receiving movement from said piston means; the other of said fluid passage means having both an entrance to and an exit from said rotor means centered on said spin axis; separate stationary fluid passage means connetced to said entrance and said exit of said other fluid passage means; rotor drive means drivingly connected to said rotor means for spinning said rotor means.

5. The mechanical-fluid power converter set forth in claim 4 and drive means operatively connecting said piston drive means and said rotor drive means for providing a fixed relationship between piston speed and rotor speed.

6. The mechanical-fluid power converter set forth in claim 4 and a variable speed rotor drive power source connected to said rotor drive means for varying rotor speed independently of piston speed.

7. A mechanical-fluid power converter comprising rotor means having a looped fluid passage and a circular fluid passage; said passages intersecting at mutually perpendicular angles at a reaction chamber centered on the rotors spin axis; said circular fluid passage being centered on a power axis that intersects with and is perpendicular to said spin axis; power piston means supported by said rotor means for rotation about said power axis through said circular passage and said reaction chamber; said looped fluid passage having both an entrance to and an exit from said rotor means centered on said spin axis; a stationary fluid passage connected to the entrance of said looped fluid passage; a stationary passage connected to the exit of said looped fluid passage; piston drive means drivingly connected to said piston means for imparting movement to and transmitting movement from said piston means; rotor drive means drivingly connected to said rotor means for spinning said rotor means.

8. The mechanical-fluid power converter set forth in claim 7 and said piston drive means comprising a gear train having an orbital gear rotatable about said power axis and connected to said piston means, an input-output power gear supported for rotation about the spin axis and in mesh with said orbital gear.

9. The mechanical-fluid power converter set forth in claim 8 and a gear train operatively connecting said input-output power gear to said rotor means for providing a fixed speed ratio between said rotor means and said piston means.

10. The mechanical-fluid power converter set forth in claim 8 and a variable speed rotor power source drivingly connected to said rotor means for varying the speed of said rotor means independently of the speed of said piston means.

References Cited UNITED STATES PATENTS 3,194,163 7/1965 Lee l03-l 3,212,443 10/1965 Hosterman 103l 3,3 06,336 2/1967 Zenkner.

ROBERT M. WALKER, Primary Examiner 

